The present invention relates to a device for adjusting the position of a strap return element, of in particular a safety belt for an automobile vehicle.
On most vehicles, this strap return element is disposed on an anchoring member fixed to the body of the vehicle at a height suitable for the majority of users of normal size.
However, this height is unsuitable for certain users and in particular persons of small size.
In order to solve this problem, a number of devices are known in the art for adjusting the height of this strap return element.
For example, there is known from the document FR 2 484 343 a device for adjusting the height of an anchoring point of a safety belt in which a slide moves along a screw-threaded support rod within the range of adjustment of the anchoring, said rod being rotatively mounted between the walls of a case fixed to an element of the body of the vehicle. The front side of this slide carries a member for anchoring the belt and its rear side carries an element for preventing the rotation of the slide which guides it along the inner wall of the case.
A device is also known from the document FR 2 488 201 for adjusting the height of a return element of a vehicle safety belt, comprising an adjusting element carrying the return element with a lock which engages in stop notches of a rectilinear guide, the lock being capable of being disengaged by an operating mechanism.
A device is also known from the document FR 2 482 539 for adjusting the anchoring point of a safety belt disposed above the shoulder of an occupant of a vehicle, in which the anchoring point is carried by a slideway cursor movably mounted in a slideway and held in position by a pawl which cooperates with a series of orifices provided in the slideway.
The document FR 2 513 887 discloses a device for adjusting the height of the upper member of a shoulder strap of a safety belt. This device comprises a slideway mounted on the body of the vehicle and provided with a guide slot and cavities in which enters at least one locking member mounted on a slide which carries the member of the shoulder strap and is lockable and unlockable by a manual operating element.
The document FR 2 543 838 discloses an anchoring device for the upper point of a safety belt, comprising a rail having a plurality of apertures which are in two parts, and a locking lug which is controlled by an operating knob. The adjustment of the position of the anchoring point is achieved by extracting the lug from the aperture, shifting the slide and re-introducing the lug in another aperture.
Lastly, the document FR 2 536 288 discloses a device for adjusting the height of a safety belt for an automobile vehicle, comprising a guiding slideway having two sides, locking openings disposed one above the other, and a carriage which is movable in the slideway, this carriage carrying a fixing or return member of the belt and including stop elements which may be transversely shifted relative to the direction of movement of the carriage by a button in opposition to the action of a spring for changing from a locking position to an unlocking position.
However, all these devices have a number of drawbacks, in particular as concerns the possibility of adjustment, their relatively complex structure and consequently their relatively high manufacturing and mounting costs.
Furthermore, in most of the known devices, the locking elements are biased to their locking position by resilient means which exert thereon a relatively large maintaining force. This obliges the user who desires to shift the strap return element to exert on the elements for shifting the locking means a relatively great force for shifting the locking means to their retracted position and thereby permit the shifting of the strap return element.